Can someone give me the low down on what a saddle description means when it is referring to bar sizes, what's the difference between them, and what type of bars generally fit what type of horses. I'm really confused on this issue.
THanks!

There are are a lot of questions asked about tree sizes. There are several different sizes of trees commonly found in saddles. Here they are listed from smallest to largest.

Semi Bar, Semi Quarter Horse bar - This type usually has a gullet width of about 6 1/2 inches.

Quarter Horse Bar - This type usually has a gullet width of about 6 3/4 inches. there are variations because of a makers opinion of what a Quarter Horse tree actually measures. Some makers do not carry a tree size larger than a 6 3/4 inch and therefore are not aware that there is a tree size larger on the market commonly referred to as a Full Quarter Tree with a gullet size of 7 inches.

Full Quarter Horse Bar - This size usually has a gullet width of 6 3/4 inches up to 7 inches.

Different makers tend to give different gullet dimensions in Quarter Horse and Full Quarter Horse trees. There are variations because of a makers opinion of what a Quarter Horse tree actually measures. These makers may call the regular Quarter Horse tree a Full Quarter Horse Tree. There is only way one way to be sure of the gullet width, ask the dealer what the gullet width is on the saddle you may be interested in. Be sure to get numbers and not just the term Quarter Horse tree or Full Quarter Horse tree if you need a gullet a certain size.

I have a quarter horse that you can definitley see he has a wither. He has a quarter horse bars. I also have a halter paint horse. that had no withers, because he was so massive around and he has a full bars saddle. It helps to fit him all the way around and causes the saddle to slip less. Your saddle should sit around your horses shoulders NOT on top of them. What size horse are you trying to fit? Do you have any pictures?

Thanks Quartersalltheway for an excellent response. NO wonder I've been confused.

My QH mare has a straight, long back. As far as her withers go, they are definitely there, but not what I would consider prominant. Here are some pics, which btw, are from the summer when I first brought her home. She has put on a considerable amount of weight since then....[/img]

I don't know if this will help of be of no use but I'll try anyway.
The sorrel, Buster wears a full QH bars saddle with a 7" gullet. The dun Appaloosa, Peaches, has the same girth measurement but that saddle is too big.

there is actually a test you can do. Take a hanger or something that bends and molds anp put it over their withers where it would sit. Then take that and go two inches down and measure that however many inches it is, is the size you will need for bar size. Someone told me this once and I tried it and it worked for me. What kind of a sadlle do you use on her now?